Asa his son reigned - If Rehoboam was (Kg1 12:8 note) not more than 21 years old at his accession, Asa, when he mounted the throne, must have been a mere boy, not more than 10 or 11 years of age.

The land was quiet ten years - The great blow struck by Abijah Ch2 13:15-19, his alliance with Syria Kg1 15:19, and the rapid succession of sovereigns in Israel during the earlier part of Asa's reign Kg1 15:25-33, would naturally prevent disturbance on the part of the northern kingdom. The tender age of Asa himself would be a bar to warlike enterprises on the part of Judah.

The land is yet before us - i. e., "unoccupied by an enemy" - "the land is open to us to go where we please." Compare Gen 13:9. The fortification of the strongholds would be an act of rebellion against Egypt, and it might be expected that the Egyptians would endeavor to put a stop to it.

The men of Judah served as heavy-armed troops, while the Benjamites were light-armed. Their numbers accord well with those of Ch2 13:3. As the boundaries of Judah had been enlarged Ch2 13:19, and as for ten years at least there had been no war Ch2 14:1, the effective force had naturally increased. It was 400, 000; it is now 580, 000.

Zerah the Ethiopian is probably Usarken (Osorkon) II, the third king of Egypt after Shishak, according to the Egyptian monuments. Osorkon II may have been by birth an Ethiopian, for he was the son-in-law, not the son, of the preceding monarch, and reigned in right of his wife. The object of the expedition would be to bring Judaea once more under the Egyptian yoke.

An host of a thousand thousand - This is the largest collected army of which we hear in Scripture; but it does not exceed the known numbers of other Oriental armies in ancient times. Darius Codomannus brought into the field at Arbela a force of 1,040, 000; Xerxes crossed into Greece with certainly above a million of combatants.

The "valley of Zephathah" - not elsewhere mentioned - is probably the broad Wady which opens out from Mareshah (marginal reference) in a northwesterly direction, leading into the great Philistine plain. Zerah, on the advance of Asa, drew off into the wider space of the Wady, where he could use his horsemen and chariots.

The defeat of Zerah is one of the most remarkable events in the history of the Jews. On no other occasion did they meet in the field and overcome the forces of either of the two great monarchies between which they were placed. It was seldom that they ventured to resist, unless behind walls. Shishak, Sennacherib, Esarhaddon, Nebuchadnezzar, were either unopposed or only opposed in this way. On the one other occasion on which they took the field - under Josiah against Necho - their boldness issued in a most disastrous defeat Ch2 35:20-24. Now, however, under Asa, they appear to have gained a complete victory over Egypt. The results which followed were nicest striking. The Southern power could not rally from the blow, and, for above three centuries made no further effort in this direction. Assyria, growing in strength, finally, under Sargon and Sennacherib, penetrated to Egypt itself. All fear of Egypt as an aggressive power ceased; and the Israelites learned instead to lean upon the Pharaohs for support (Kg2 17:4; Kg2 18:21; Isa 30:2-4, etc.). Friendly ties alone connected the two countries: and it was not until 609 B.C. that an Egyptian force again entered Palestine with a hostile intention.